Reply To: Arbitrary precission integer arithmetic hardware help

Contrary to what everyone else is saying, this isn’t possible on the Mill as we know it.

However, it seems likely that it can be made to be possible. Unfortunately, it may be more trouble than it’s worth…maybe it’ll be in the GenASM but never actually implemented like Decimal. However, here’s my take:

1. Have a new type of data that can be operated on aside from float, integer, and pointer: the int60. The int60 is like a pointer in that ops on it are only specified for pointer-size.
2. To use int60, a SpecReg has to be set indicating one of the three-bit patterns in the reserved bits as the int60 pattern (default 000).
3. SpecRegs also set the handlers for int60 overflow ops. There are ADD, SUB, MUL, DIV, MOD, DIVMOD, AND, OR, NOT, XOR, SHL, SHR, TOINT (with output width, overflow behavior, and output signedness arguments), FROMINT (with input signedness arguments), and DROP (explicitly-called destructor op).
4. Basically, treat as 60-bit int when the flag bits are the three-bit “this is actually an integer” pattern and call routines as a pointer when otherwise.